Clock signals may be used in an electronic system for such purposes as synchronizing operations of a processor core or radio; keeping track of time; initiating periodic activity; and so forth. A typical electronic system includes one or multiple oscillators to generate periodic signals from which the system's clock signals are derived. One type of oscillator is a relaxation oscillator, such as a resistor-capacitor (RC)-based oscillator, which has a relaxation frequency that is a function of one or multiple capacitances and one or multiple resistances of the oscillator. Another type of oscillator is a crystal-based oscillator, which has a resonant frequency that is set by the mechanical resonance of a vibrating piezoelectric crystal.